package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.util.Collections;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }
    //定义阻塞队列
    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    //创建线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    //创建线程任务
    private class VoucherOrderHandler implements Runnable {

        @Override
        public void run() {
            //不断的从阻塞队列里取出用户id 订单信息
            while (true) {
                //从阻塞队列里取出订单信息
                try {
                    VoucherOrder voucherOrder = orderTasks.take();
                    //创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单失败", e);
                }
            }
        }
    }

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        //创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        //判断是否获取锁成功
        if (!isLock) {
            log.error("不允许重复下单");
            return;
        }
        //获取成功
        try {
            //获取当前对象的代理对象（事务）
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            //释放锁
            lock.unlock();

        }
    }

    private IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        //1.执行Lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                UserHolder.getUser().getId().toString()
        );
        int r = 0;
        if (result != null) {
            r = result.intValue();
        }
        if (r != 0) { //2.判断结果是否为0,不为0,代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //2.2.为0,有购买资格,把下单信息保存到阻塞队列
        VoucherOrder voucherOrder = new VoucherOrder();
        long orderId = redisIdWorker.nextId("order");//订单id
        voucherOrder.setId(orderId);
        voucherOrder.setUserId(userId);//用户id
        voucherOrder.setVoucherId(voucherId);//代金券id
        //放入阻塞队列
        orderTasks.add(voucherOrder);
        //获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //3.返回订单id
        return Result.ok(orderId);
    }




    /*@Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询优惠券信息
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //判断voucher不为null
        if (voucher == null) {
            return Result.fail("优惠券信息不存在");
        }
        //2.判断秒杀是否开始
        //2.1秒杀尚未开始返回异常
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            return Result.fail("秒杀尚未开始");
        }
        //2.2秒杀已结束返回异常
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            return Result.fail("秒杀已经结束");
        }
        //3.判断库存是否充足
        if (voucher.getStock() < 1) {
            //3.1库存不足返回异常
            return Result.fail("库存不足！");
        }*/

        /*Long userId = UserHolder.getUser().getId();
        //创建锁对象
        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        //判断是否获取锁成功
        if (!isLock) {
            return Result.fail("请勿重复抢购");
        }
        //获取成功
        try{
            //获取当前对象的代理对象（事务）
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        }finally {
            //释放锁
            lock.unlock();
        return createVoucherOrder(voucherId);
    }*/


    @Resource
    private RedissonClient redissonClient;

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //4.一人一单
        Long userId = voucherOrder.getUserId();
//        RLock redisLock = redissonClient.getLock("lock:order:" + userId);
//        //获取锁
//        boolean isLock = redisLock.tryLock();
//        //判断是否获取锁成功
//        if (!isLock) {
//            return Result.fail("请勿重复抢购");
//        }

        //4.1 查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        //4.2 判断是否存在订单
        if (count > 0) {
            //用户已经购买过2.返回异常                                                                                                                     111111
            log.error("用户已经购买过了!");
            return;
        }
        //5 库存充足扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1") //set stock=stock-1
                .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock", 0)  //where id=? and stock>0
                .update();
        if (!success) {
            //扣减失败返回异常
            log.error("库存不足!");
            return;
        }
        //6.创建订单，返回订单id
        save(voucherOrder);
    }
}

